Anti-drain back/pressure relieved filter cartridges

Abstract

A filter including a combination bypass valve and anti-drain valve is disclosed herein. The filter includes an annular valve support which supports an annular valve member disposed between the support and a filter cartridge. The valve support has an inner sleeve portion which seats against an end plate and an outer sleeve portion including bypass louvers therethrough. The valve member has an expandable collar portion which normally seals the bypass louvers and a skirt portion which normally seals inlet openings extending through the end plate. The skirt permits flow through the inlet openings into the filter but prevents out of the filter through the inlet openings. Excessive pressure caused by a clogged filter element deflects the expandable collar away from the bypass louvers thereby permitting flow to bypass the filter element.

What is claimed is: 
     
       1. In a lubricating oil filter cartridge, a housing with an annular filter element therein; the annular filter element having a hollow core, the housing including an end plate having a central outlet therethrough surrounded by a plurality of inlet openings for allowing lubricating oil to enter the housing through the inlet openings in the end plate, to flow through the filter element to the hollow core thereof and to flow out of the filter element through the central outlet, the improvement comprising: an annular valve support disposed between the end plate and the filter element, the annular valve support having an inner sleeve bearing against the end plate proximate the outlet and an outer sleeve spaced from the inner sleeve to define an annular space therebetween, the outer sleeve including a plurality of openings therethrough communicating with the annular space and including louvers adjacent to the openings, the louvers extending into the annular space and directing the lubricating oil to flow through the openings, the outer sleeve having a radially extending flange extending outwardly therefrom for supporting the annular filter element; and   an annular valve member having a radially extending skirt overlying the inlet openings in the end plate, the radially extending skirt functioning as an anti-drain back valve by preventing oil from flowing out of the filter through the inlet openings while allowing oil under pressure to deflect the flaps and to flow pass the annular valve member and through the annular filter element when the annular filter element is not clogged, the valve member further including an expandable collar fitting around the outer sleeve and covering the openings, the expandable collar spreading to uncover the openings as the liquid flows over the louvers and between the collar and the outer sleeve when the filter element becomes clogged so as to bypass the clogged filter.   
     
     
       2. The improvement of claim 1, wherein the annular valve member is disposed between the filter element and the outer sleeve of the valve support. 
     
     
       3. The improvement of claim 2, wherein the filter element has an end cap with an inner axially extending flange, the inner axially extending flange of the end cap engaging the expandable collar. 
     
     
       4. The improvement of claim 1, wherein the expandable collar is cylindrical and has an end which terminates outside of the outer sleeve. 
     
     
       5. The improvement of claim 4, wherein the valve member is made of a resilient resinous material. 
     
     
       6. The improvement of claim 5, wherein the valve member is made of silicone. 
     
     
       7. The improvement of claim 6, wherein the annular valve support is made of steel or plastic. 
     
     
       8. The improvement of claim 1, wherein the valve member is configured and arranged for opening at a selected pressure indicative of the filter media being clogged, the selected pressure being higher at low temperatures than at operating temperature. 
     
     
       9. The improvement of claim 8, wherein the valve member comprises a temperature sensitive elastic material having an elastic modulus which increases as temperature drops. 
     
     
       10. The improvement of claim 9, wherein the material is silicone. 
     
     
       11. The improvement of claim 1, wherein the expandable collar has a free end disposed beyond the openings and wherein the louvers extend from the annular space toward the annular free end to direct the liquid toward the free end. 
     
     
       12. The improvement of claim 11, wherein the openings extending axially with respect to the annular valve support and have a first end and a second end, the first end being adjacent to the annular free end of the collar and having a single louver extending therefrom toward the inner sleeve.